1. Introduction
2. Avalonia UI
3. Dependency Injection
4. MVVM Design
5. Dialogs and Tools
6. Unit Testing
7. Reactive
8. Deployment
9. Assembly Trimming
10. Multiple Environments
You can develop an Avalonia application and run it on Windows, MacOS and Linux without issues. You'll most likely only experience minor problems with file paths, permissions and such.
If you also want to develop for Android and iOS, then things get a bit more complicated to test.
Did you know that you can setup all environments to run on your machine?
You'll need KVM+QEMU, with Virtual Machine Manager. Do NOT use VirtualBox (slow) nor the Android Emulator (very slow). QEMU will provide near-native performance but can be a bit complex to setup (once).
It is also possible to pass a physical GPU to your virtual machines, allowing you to game at near-native performance, but that's even more complex to setup and requires two graphic cards. If you have a dual-graphics laptop, here's a tutorial to set it up, requiring you to close your session when switching OS. The other option is to have two physical cards in your computer, one for Linux and one for Windows/Mac. For the sake of .NET programming, you won't need GPU passthrough.
You can easily install Windows 10 in KVM. There are plenty of guides online, just google it, I'm not sure what tutorial is the best.
For Android, install Android-x86. You'll need at least 5GB of space to debug and run your apps.
For MacOS, Install MacOS on KVM. XCode alone takes about 8GB so you'll need about 55GB. Unfortunately, MacOS is not usable without GPU passthrough (works only for simple tasks like XCode) so you'll need to set it up with GPU passthrough which can be extremely difficult and only certain GPUs may be supported. Another option is to rent access to a Mac online.
For iOS... there are no KVM emulators for iPhone, but MacOS does have an emulator.
You can setup network shares in Linux using SAMBA, then access your file system with shared project files from Windows.
WARNING: Editing the same projects from Windows and Linux can cause conflicts with line endings (CR vs CRLF). Git standardizes line endings anyway.
I personally got JetBrains Rider installed in Linux and Visual Studio installed in Windows (for the cases where I need Visual Studio). I was told that Rider has issues running in MacOS without GPU; that remains to be tested.
To debug Android applications, you'll need Android Connect android-tools package.
Get the Android IP address. Pass your QEMU instance name to the 2nd command to get the IP. If you get no results, try with sudo.
virsh list
virsh domifaddr android-x86
Then, type this command with the IP address. It's that simple!
adb connect 192.0.0.0
In Rider, the QEMU instance automatically shows up as a physical device. Hit run, and it runs in Android. Easier than expected!
For iOS, that remains to be tested. There is an iOS emulator in MacOS. Remains to be seem whether it works with decent performance without GPU.
QEMU also works on Windows but does not have the same performance. You can try improving QEMU performance by enabling HAXM.
Android Emulator in Windows should have decent performance with HAXM enabled.
If you get your environment setup in Windows, you can open up a discussion to let us know what works or not for you.
If you get your environment setup in MacOS, you can open up a discussion to let us know what works or not for you.